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We use sessions when we want to preserve certain data across subsequent accesses. PHP allows us to use different handlers when we’re using sessions. The default one is filesystem, but we can change it with session.save_handler in the php.ini. session.save_handler defines the name of the handler which is used for storing and retrieving data associated with a session. We also can create our own handler to manage sessions. In this post we’re going to create a custom handler to store sessions in a node.js service. Let’s start:

A simple usage of sessions with PHP. If we reload the page our counter will be incremented by one. We’re using the default session handler. It works without any problem.

The idea is create a custom handler to use a server with node.js to store the session information instead of filesystem. To create custom handlers we need to use the PHP function: session_set_save_handler and rewrite the callbacks for: open, close, read, write, destroy and gc. PHP’s documentation is great. My proposal is the following one:

Continuing with my experiments of node.js, this time I want to create a Web console. The idea is simple. I want to send a few command to the server and I display the output inside the browser. I can do it entirely with PHP but I want to send the output to the browser as fast as they appear without waiting for the end of the command. OK we can do it flushing the output in the server but this solution normally crashes if we keep the application open for a long time. WebSockets again to the rescue. If we need a cross-browser implementation we need the socket.io library. Let’s start:

The node server is a simple websocket server. In this example we will launch each command with spawn function (require(‘child_process’).spawn) and send the output within the websoket. Simple and pretty straightforward.

And that’s all. In fact we don’t need any line of PHP to perform this web console. Last year I tried to do something similar with PHP but it was a big mess. With node those kind of jobs are trivial. I don’t know if node.js is the future or is just another hype, but it’s easy. And cool. Really cool.

You can see the full code at Github here. Anyway you must take care if you run this application on your host. You are letting user to execute raw unix commands. A bit of security layer would be necessary.

The inspection of the error logs is a common way to detect errors and bugs. We also can show errors on-screen within our developement server, or we even can use great tools like firePHP to show our PHP errors and warnings inside our firebug console. That’s cool, but we only can see our session errors/warnings. If we want to see another’s errors we need to inspect the error log. tail -f is our friend, but we need to surf against all the warnings of all sessions to see our desired ones. Because of that I want to build a tool to monitor my PHP applications in real-time. Let’s start:

What’s the idea? The idea is catch all PHP’s errors and warnings at run time and send them to a node.js HTTP server. This server will work similar than a chat server but our clients will only be able to read the server’s logs. Basically the applications have three parts: the node.js server, the web client (html5) and the server part (PHP). Let me explain a bit each part:

The node Server

Basically it has two parts: a http server to handle the PHP errors/warnings and a websocket server to manage the realtime communications with the browser. When I say that I’m using websockets that’s means the web client will only work with a browser with websocket support like chrome. Anyway it’s pretty straightforward swap from a websocket sever to a socket.io server to use it with every browser. But websockets seems to be the future, so I will use websockets in this example.

If you want to know more about node.js and see more examples, have a look to the great site: http://nodetuts.com/. In this site Pedro Teixeira will show examples and node.js tutorials. In fact my node.js http + websoket server is a mix of two tutorials from this site.

The web client.

The web client is a simple websockets application. We will handle the websockets connection, reconnect if it dies and a bit more. I’s based on node.js chat demo

The server part:

The server part will handle silently all PHP warnings and errors and it will send them to the node server. The idea is to place a minimal PHP line of code at the beginning of the application that we want to monitor. Imagine the following piece of PHP code